1. Field of the Invention
This invention relates to computer storage and server systems, and more particularly to such systems providing multi-disk storage in a single, field replaceable unit.
2. Description of the Related Art
Many enterprises employ server or storage systems that include multiple disk drives and other components. These enterprises may require a high degree of reliability from their server and storage computer systems. If a component of the server or storage system fails, it may cause the entire system to fail or at least to operate in a degraded mode. Since many enterprises cannot afford extended down time from such component failures, it is desirable to be able to quickly address such component failures. One way this problem has been addressed is to make many of the components of such computer systems to be field replaceable or even hot swappable. Field replaceable means that a failed component may be easily replaced in the field with a new, functional component. For example, in many computer systems components such as the hard drives, power supplies, fans, and even CPU's may be field replaceable. Hot swappable refers to the ability to replace such a component without powering down the system. Ideally, hot swappable means that a component such as a hard drive can be removed and replaced with a new hard drive without powering down the system and the new drive will be automatically recognized by the system.
However, in order to support field replacement or hot swapping of components, the system must be designed to allow easy access to all components that are to be field replaceable or hot swappable. This requires that the system have access panels and other openings as necessary to allow access to the components that are to be field replaceable or hot swappable. In addition to access panels that may easily be opened in the field, the system must also be internally designed to allow access to the replaceable components. For example, the replaceable components should not be blocked by other components. Also, replaceable and hot swappable components are often mounted in a bracket or socket for easy removal and insertion. Special sockets may also be required for hot swappable devices to insure that hot removal or insertion does not interrupt ongoing transactions in the computer or storage system.
The access panels, internal spacing, special sockets, etc., required to support field replacement or hot swappability means that components may not be packaged as densely in such systems as would otherwise be possible. Also, the requirements to support field replacement and/or hot swappability may make a system more expensive. It would be desirable to still achieve some of the benefits of field replaceability without sacrificing the loss of component density and the added expense of current systems that support field replaceable components.